This cross-sectional case-control study was carried out on 46 consecutive treatment- naïve patients with sporadic CRC proved by colonoscopy, histopathology and abdominal computed tomography. All cases and 20 matching controls had tumour staging with TNM and Duke's staging syrstems. Faecal tumour test was assessed in all patients 24 males, 22 females, whose age 50% of there above 50 yrs. Results showed that rectal lesions found during colonoscopy in 47.8% while colonic lesions in 52.2%. Masses were encountered (in 67.4%, 31 cases) and adenocarcinoma was the commonest type (76.1 %, 35 cases) followed by mucinous adenocarcinoma (15.2 %, 7 cases).
The faecal levels of tumour M2-PK™ were significantly higher (P0.05). Applying
ROC curves, at a cut-off value of 3.9
U/ml, faecal tumour M2-PK™ was 97.8% sensitive and 85% specific for detection of CRC with AUROC= 0.96.
In conclusions, faecal tumour M2-PK™ was a sensitive and specific marker for detection of CRC at values ≥ 3.9 U/ml and positively correlated with the tumour grade and stage.
Introduction
Colorectal cancer (CRC) represents the third most common tumour worldwide and is still burdened by significant morbidity and mortality despite several therapeutic improvements (Gellad and Provenzale, 2010). CRC incidence rates are rapidly increasing due to the effect of many risk factors, including smoking, phyrsical inactivity, obesity, red and processed meat consumption, as well as excessive alcohol intake (Jemal et al., 2011).
In Egypt, CRC is one of the most
common malignant neoplasms. Its incidence ranges between 2-6 % of the total number of cancer cases reported annually and it ranks as the sixth most common cancer in both males and females (Zalata et al., 2000 and ZeenEldin et al., 2012). The median age of CRC cases in Egypt is 48 years for both males and females (El-Attar, 2005).
Most cases of CRC develop from polyps. Three types of polyps occur: hamartoma (junior polyp), hyperplastic mucosal proliferation (hyperplastic polyp) and adenomatous polyp. Adenomatous is the only premalignant type, it may be tubular, villous, or tubulovillous, with villous adenomas the most likely to be cancerous. Adenomatous polyps may be either sessile (flat) or pedunculated (stalked), with sessile types being more likely to progress to cancer. Finally, polyps greater than 2.5 cm are five times more likely to be cancerous than those less than 1.5 cm. Overall, once an adenomatous polyp forms, it takes at least 5 years of growth to reach clinical significance, suggesting the need to initiate screening and perform routine follow-up evaluation to identify polyps that are of concern before they become cancerous (Steinberg, 2012).
CRC mortality rates can be decreased by early diagnosis through screening. However, the present CRC screening techniques (colonoscopy, faecal occult blood test (FOBT) and serum carcinoembryonic antigen (CEA) testing are limited by their difficulties and costs beside uncertain or delayed results (Foo et al., 2012). Hence, the identification of biomarkers that are simple, non - invasive, cost-efficient and reasonably sensitive / specific is
urgently needed (Xi et al., 2014).
A gold standard for early non invasive detection of CRC in adult Egyptians is to assess faecal tumour M2-PK™ (ScheBo test) which is a key enzyme within glycolyrsis, a process that catalyzes the conversion of phosphoenolpyruvate (PEP) to pyruvate. Depending upon the metabolic functions of the tissues, different isoenzymes of pyruvate kinase are expressed. During tumour formation, the tissue-specific isoenzymes disappear and the pyruvate kinase isoenzyme type M2 is expressed (Gupta and Bamezai, 2010).
The aim of the present study, therefore, was to assess faecal tumour M2-PK™ (ScheBo test) as a marker for CRC detection in adult Egyptian patients.
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